SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a0ff46c7da9d4a3137516cc342594c861788069059eb7034cac272bd1d7d9a6' 
  AND token = 'liGjQMz0jMgJKJKyIfbyIvSvz0AO76iPCzvE/NlKuWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}